In an absorbent article such as an absorbent pad for light incontinence which is used by being attached on the inside of a disposable diaper, an absorbent sheet is conventionally utilized which is obtained by sandwiching particles of high-absorbent resin between two sheet members formed of nonwoven fabric or the like to fix the particles therebetween.
Japanese Patent Application Laid-Open No. 2007-130818 (Document 1) is related to a composite sheet. In the composite sheet, a plurality of concave portions are formed on one of two sheets, and functional material such as absorbent polymer is held in the concave portions. In a manufacturing apparatus for the composite sheet of Document 1, a first sheet is supplied to an engaging region between two rolls having concave-convex shapes engaging with each other, and the first sheet is held along the concave-convex shape on a periphery of a first roll by exerting a suction force on the first sheet. Subsequently, by exerting the suction force through the first sheet, functional material stored in a duct facing the first roll is held on the first sheet. Then, a second sheet is laid and bonded on the first sheet, to complete the composite sheet.
International Publication No. WO 2006/15141 (Document 2) is related to a process of producing sandwich structures with particulate material pattern. In an apparatus of Document 2, after adhesive is applied onto a carrier material, indentations are formed in the carrier material. Particulate material expelled from one of recesses of a transfer device is transferred into a corresponding indentation, and then, a cover material is overlaid and bonded on the carrier material.
Incidentally, in the manufacturing apparatus of Document 1, since functional material in the duct is supplied onto the first sheet by gravity and air blow, the functional material is supplied on not only the concave portions of the first sheet but also portions of the first sheet other than the concave portions. Thus, it is difficult to produce a composite sheet where existence regions of the functional material are arranged in a dotted pattern. The functional material is held on the first sheet with the suction force by the first roll until the first sheet which has passed through the duct is covered with the second sheet. However, since a rotation speed of the roll is normally high in such apparatus, scattering of the functional material from the first sheet may occur by a centrifugal force.
In the apparatus of Document 2, the particulate material is expelled toward the carrier material from the transfer device. Thus, when the particulate material collides with the carrier material, the particulate material may scatter to the outside of the indentations. Since adhesive is applied on the carrier material in advance, a distance between the transfer device and the carrier material can't be decreased below a certain value.